The Fairy-Land of Science eBook

Again, some flowers close whenever rain is coming.
The pimpernel (Anagallis arvensis) is one of these,
hence its name of the “Shepherd’s Weather-glass.”
This little flower closes, no doubt, to prevent its
pollen-dust being washed away, for it has no honey;
while other flowers do it to protect the drop of honey
at the bottom of their corolla. Look at the
daisies for example when a storm is coming on; as
the sky grows dark and heavy, you will see them shrink
up and close till the sun shines again. They
do this because in each of the little yellow florets
in the centre of the flower there is a drop of honey
which would be quite spoiled if it were washed by
the rain.

And now you will see why cup-shaped flowers so often
droop their heads — think of the harebell, the
snowdrop, the lily-of-the-valley, the campanula,
and a host of others; how pretty they look with their
bells hanging so modestly from the slender stalk!
They are bending down to protect the honey-glands within
them, for if the cup became full of rain or dew the
honey would be useless, and the insects would cease
to visit them.

Week 29

But it is not only necessary that the flowers should
keep their honey for the insects, they also have to
take care and keep it for the right kind of insect.
Ants are in many cases great enemies to them, for
they like honey as much as bees and butterflies do,
yet you will easily see that they are so small that
if they creep into a flower they pass the anthers without
rubbing against them, and so take the honey without
doing any good to the plant. Therefore we find
numberless contrivances for keeping the ants and other
creeping insects away. Look for example at the
hairy stalk of the primrose flower; those little hairs
are like a forest to a tiny ant, and they protect the
flower from his visits. The Spanish catchfly
(Silene otites), on the other hand, has a smooth,
but very gummy stem, and on this the insects stick,
if they try to climb. Slugs and snails too will
often attack and bite flowers, unless they are kept
away by thorns and bristles, such as we find on the
teazel and the burdock. And so we are gradually
learning that everything which a plant does has its
meaning, if we can only find it out, and that even
very insignificant hair has its own proper use, and
when we are once aware of this a flower-garden may
become quite a new world to us if we open our eyes
to all that is going on in it.

But as we cannot wander among many plants to-day,
let us take a few which the bees visit, and see how
they contrive not to give up their honey without getting
help in return. We will start with the blue
wood-geranium, because from it we first began to learn
the use of insects to flowers.